The present invention relates generally to systems for recycling woodwaste and more particularly to an apparatus and method for separating contaminates from woodwaste to produce mulch, and material for potting mix, and the like.
Yard waste is usually contained in plastic bags where it is picked up by garbage trucks and taken to land fills. With increased tipping fees at waste disposal sites (landfills) and a shortage of such sites in urban areas, there is an ever-increasing incentive to separate woodwaste from the urban waste stream and to recycle it into other usable products.
The vast majority of this material is transported to landfills for burial, adding to the nation's solid waste disposal crisis.
Burying woodwaste in landfills is not only a waste but is becoming an unmanageable problem in terms of finding adequate space for such landfills. It is difficult to document the amount of woodwaste being land-filled nationwide. In addition to finding suitable landfill areas, landfilling is expensive. The environmental impact of landfilling is also just now being confronted through federal cleanup and monitoring programs like the EPA Superfund. The simplest way to lessen the environmental impact is to decrease the amount of woodwaste going to landfills.
Various equipment is currently on the market for processing wood and yard waste debris. Private companies and municipal public work department currently utilize grinders to grind up the woodwaste for recycling and to use as boiler fuel, landscaping products, soil additives and the like.
Contaminated (marginal) woodwaste can be processed only if the contaminates, such as plastics and sand, can be efficiently and economically removed. If the contaminants are removed, the processed product may be marketable as landscaping products and the like.
An object of the present invention is to provide an economically-viable alternative to landfilling woodwaste.
Yet another object of the present invention is to provide high quality, marketable end products from urban woodwaste.
Prior U.S. patents which process woodwaste for the removal of contaminants, such as plastic, can be seen in the Clinton U.S. Pat. No. 5,865,317 and No. 5,915,565, both of which provide systems for processing woodwaste. The woodwaste is received at one end of the system and metal contaminants are removed from the woodwaste which is then separated according to size for further processing. Unwanted papers and plastic contaminants are removed from the woodwaste using a cyclone and a door and a vacuum system. The cyclone may be positioned in the system for removing plastics prior to feeding the woodwaste into a trommel. In the J. W. & D. R. Bryan U.S. Pat. No. 1,244,952, a method of separating and recovering domestic refuse is provided using a trommel having different sized screens for rotating the pulverized domestic refuse through. The screens are rotated while an electric fan provides a current of air over each of the screens to draw dust laden air from the trommel. The Maehata et al. U.S. Pat. No. 6,467,628 is a plastic chip separator which electrostatically separates different kinds of crushed plastic pieces and sorts them according to kind. The Webb et al. U.S. Pat. No. 3,970,546 is a method and apparatus for separating non-ferrous metal from waste material and utilizes a drum and a D.C. corona electrode and an A.C. corona electrode and a D.C. static electrode and a splitter. The material is successively subjected to the D.C. corona discharge, the A.C. corona discharge, and a D.C. electrostatic field to separate non-ferrous material from municipal waste. The Xiao et al. U.S. Pat. No. 6,452,126 is an electrostatic separation using separating waste plastics from beverage bottles, PVC from PET, and packaging plastics, PE from PP. The Roberto U.S. Pat. No. 5,335,786 is a method and apparatus for separating and recycling of plastic. The Vikio U.S. Pat. No. 5,084,161 is a method and apparatus for the removal of light material from fiber suspension and utilizes a separation device, such as a vibrating screen, vibrating drum, curved screen or inverted cyclone for removing plastic. The Wilson U.S. Pat. No. 3,888,351 is an automatic refuse reclamation system which initially separates light paper, light plastics, magnetic materials, large items and fines. The Hayashi et al. U.S. Pat. No. 5,740,918 is an apparatus and method for density separation of plastic.
The present invention is directed towards a woodwaste and plastic processing trommel which utilizes a rotating trommel having electrodes mounted therein and a vacuum removal tube for separating chopped up plastic waste from the woodwaste.